This invention relates to hermetically sealed opto-electrical semiconductor devices including an electricity-to-light converting semiconductor devices such as a laser diode, light-emitting diode and the like and a light-to-electricity converting semiconductor devices such as a light-receiving diode, a photo-sensitive semiconductor device and the like. More particularly, the present invention relates to a semiconductor device adapted to emit or receive light in two or more directions perpendicular to the axial direction of a mount on which a semiconductor element is mounted.
Semiconductor devices having an electricity-to-light converting function or a light-to-electricity converting function should have such a construction that a semiconductor element be protected from an ambient and yet the semiconductor element emit or receive light to or from the exterior. As a casing for use in an opto-electrical semiconductor device which permits the transmission of light to or from the exterior in two or more directions included in one plane, suggested is a structure comprising a transparent glass cylinder which houses a semiconductor element therein and has its opposite ends sealed with metallic electrodes, respectively. The external surface of this glass cylinder is locally ground or transformed into a flat surface at light-transmitting portions of the cylinder wall for the purpose of achieving desired light-passing characteristics. With an opto-electrical semiconductor device having such structure, there tends to occur a lack of flatness on its flattened surface portions of the glass cylinder, with the result that light passing therethrough is scattered or loses its linearity. This drawback is attributable to locally flattened surface of the glass cylinder. In addition, since the glass cylindrical body is hermetically sealed with metallic electrodes at the opposite ends of the body, another shortcoming occurs that joint of the metallic electrode to the cylinder lacks desired strength and provides poor air-tightness.
It is accordingly an object of the present invention to provide an opto-electrical semiconductor device with excellent optical characteristics, air-tightness and mechanical strength.